1. Field of the Invention
This invention relates to moldable metallic and/or ceramic composition, to process for producing a sintered body therefrom and to products resulting from same.
2. Description of the Prior Art
It is known to produce sintered bodies from metallic or ceramic powder mixed with thermoplastic binders (such as polypropylene, methacrylate copolymer, polystyrene, ethylene-vinyl acetate copolymer, low density polyethylene, and combinations of them), or combinations thereof with plasticizer or lubricants (such as paraffin wax, diethyl phthalate, and stearic acid). It is also known to produce sintered bodies by injection molding such compositions and then removing or driving off the binder (hereinafter referred to as debinding) from the molded articles, followed by sintering the articles (U.S. Pat. No. 2,593,943).
As there is a tendency of deformation of molded bodies by gravity, or cracking or blistering with decomposed gas, during debinding of molded articles produced from these known molding compositions; molded bodies are buried in ceramic or metallic powder to prevent deformation, or heated up slowly such as at a rate of 1-10.degree. C./hour to depress generation of decomposed gas, and therefore it is necessary to brush off the powder from the surface of the debinded bodies prior to sintering, or it takes long time to drive off the binder. Thus, these known molding compositions are not satisfied for industrial production.